Some samples, such as metal hydrides, for example, are very air sensitive and possess very weak Raman signatures. As such microscopy and spectroscopy methods that utilize a conventional window material (e.g. glass, quartz, or the like) between the sample and the objective lens(es) can attenuate the Raman signal(s) by a factor of up to ten. Such conventional window materials are typically necessary such that the environmental cell assembly utilized can be evacuated and/or purged, and, optionally, a reactive gas can be introduced in a controlled manner. In other words, the sample must be protected from the outside environment. This is problematic.
Thus, what is needed in the art is an environmental cell assembly that does not incorporate a conventional window material between the sample and the objective lens(es) of a microscope or spectroscopic assembly, such that the Raman signal(s) are not significantly attenuated. This environmental cell assembly should allow for the vertical, and potentially the horizontal and rotational, adjustment of the position of the sample within the environmental cell assembly, as well as the ready evacuation of the environmental cell assembly, the introduction of a purge (i.e. inert) gas, the introduction of a reactive gas, etc. In other words, the environmental cell assembly should provide the sample with isolation from the outside environment while microscope and/or spectroscopic methodologies are employed. By meeting all of these criteria, even very weak Raman signals can be detected and utilized in further analyses.